There are five herpes viruses that are known to infect humans. They are as follows:
(1) Herpes Simplex Type 1 which causes cold sores, encephalitis and keratitis.
(2) Herpes Simplex Type 2 which causes genital and neonatal herpes.
(3) Varicella-Zoster Virus which causes chicken pox, shingles and herpes zoster.
(4) Epstein-Barr Virus which causes infectious mononucleosis and which may cause certain tumors.
(5) Cytomegalovirus which is responsible for pneumonitis in renal transplant and other immunocompromised patients, congenital malformations including mental retardation and a mononucleosis-like syndrome in young adults and recipients of blood transfusions. Cytomegalovirus infections and their complications are now at near epidemic proportions in the male homosexual population.
The herpes virus has a complex activity as is illustrated by two ailments caused by herpes viruses, namely, cold sores and genital herpes. Oral Herpes Simplex Type 1 affects most Americans by the time they are fifteen years of age. Approximately thirty to fifty percent of the population of the United States is afflicted with subsequent cases of cold sores, generally in the lip area, although not in the mouth. Occasionally the Herpes Simplex 1 virus can migrate along nerve cells invading the central nervous system, primarily the temporal lobe, to cause life-threatening encephalitis.
The patterns of infection, latency and reactivation of genital herpes caused by the Herpes Simplex 2 virus are similar to Type 1 virus. A primary infection, usually resulting from sexual contact with a partner that is shedding virus, causes highly infectious lesions on the genital organs which can spread the virus for about ten days. Immunity against the virus develops, the lesions heal, but yet some of the virus remains in the body, traveling along the nerve cells--this time to the sacral ganglia near the lower spinal cord, where it remains dormant for a time. A recurrent episode of this infection may then be caused by stress or other factors similar to those that trigger cold sores. Recurrence of this virus is more frequent in men and often follows sexual intercourse. Recurrence in women tends to be more severe. It has also been observed that women who have frequent episodes of genital herpes, and thus have high titers of antibodies to Herpes Simplex 2, have a relatively high incidence of cervical cancer.
Two viral infections of the oral mucosa are herpes simplex infections and herpangina.
Herpetic stomatitis represents a primary contact with the herpes simplex virus. After the loss of maternal antibodies to the herpes virus, the child or young adult, as a result of exposure, becomes infected. This commonly results in a condition called herpetic stomatitis. Less common forms of involvement are a herpetic dermatitis, herpetic vulvovaginitis, herpetic conjunctivitis or keratitis, and herpetic meningitis or meningoencephalitis.
Following the development of the primary herpetic disease, an antibody response confers immunity to subsequent manifestations of the primary disease. Recurrent herpetic involvement is usually confined to the lips and its manifestations differ from those of the typical herpetic stomatitis.
Acute herpetic gingivostomatitis usually strikes children and young adults. It has been observed that older people are rarely affected by this condition.
Oral herpetic disease is first manifested by a prodromal period of 24 to 48 hours, after which the oral manifestations appear. Specifically, an acute gingivitis of the marginal and attached gingiva appears and the tongue exhibits vesicular eruption and is coated. The gingivae becomes edematous and reddened. This disease is further characterized by vesicles and ulcers that can form throughout the mouth. The vesicles usually rupture approximately 24 hours after formation, leaving small ulcers surrounded by a zone of erythema. These vesicles can continue to form for up to approximately one week. Within approximately twelve to eighteen days, these lesions tend to disappear, healing without any residual scarring.
Initially, the symptoms may appear similar to other acute infections that exhibit fever, malaise, generalized discomfort and localized pain. Eating becomes difficult due to the gingiva being swollen and the presence of numerous painful ulcers. The temperature in the child ranges from 100.degree. to 104.degree. in the early stages, and returns to normal in approximately five to seven days. In the young adult, systemic manifestations are similar to those found in younger children, but are often less severe, and the temperatures usually remain under 100.degree. F. The lips may be subject to recurrent attacks of grouped vesicular lesions. Herpes Simplex Virus is the etiologic agent. The antibodies against the herpes virus are ineffective at this local site, and recurrent disease can occur despite the presence of antibodies to the disease. It seems that the virus is present in the lip epithelium, and under certain conditions, produces the disease. Some of these conditions are the rays of the sun, trauma, and emotional tension. The lip vesicles are usually size in size and quite numerous in number. They may be localized to a small area of the lips or they may cover the entire mucosa. The duration of herpes labialis is usually seven to ten days, and is often prolonged by a complicating secondary infection of the lesions on the skin close to the muco-cutaneous junction. In recurrent herpes labialis, the mouth is not involved, but there may be labial involvement in primary herpetic stomatitis.
Althouguh recurrent oral herpetic disease is unusual, it can nevertheless occur. These lesions have small vesicles surrounded by erythema. These vesicles rupture rapidly leaving small punctate ulcers. Acute gingivitis, coated tongue, and the sytemic manifestations seen in primary herpetic stomatitis are absent.